tim x
a, ( 2x - 4 ) ^ 3 = 8
b, 720 / [ 41 - ( 2x - 5 ) ] = 2^3 * 5
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14 tháng 12 2016
720 : [ 41 - ( 2x-5)] = 2^3 .5
=> 720 :[ 41- (2x-5)] = 40
=> 41 - (2x-5) = 18
=> 2x -5 = 23
=> 2x = 28
=> x=14
NN
25 tháng 11 2017
a) \(\left[\left(4x+28\right).3+55\right]:5=35\)
\(\Leftrightarrow\left(4x+28\right).3+55=35.5\)
\(\Leftrightarrow\left(4x+28\right).3+55=175\)
\(\Leftrightarrow\left(4x+28\right).3=175-55\)
\(\Leftrightarrow\left(4x+28\right).3=120\)
\(\Leftrightarrow4x+28=120:3\)
\(\Leftrightarrow4x+28=40\)
\(\Leftrightarrow4x=40-28\)
\(\Leftrightarrow4x=12\)
\(\Leftrightarrow x=12:4\)
\(\Leftrightarrow x=3\)
Vậy \(x=3\)
b) \(\left(12x-4^3\right).8^3=4.8^4\)
\(\Leftrightarrow12x-4^3=4.8^4:8^3\)
\(\Leftrightarrow12x-4^3=4.8^{4-3}\)
\(\Leftrightarrow12x-4^3=4.8\)
\(\Leftrightarrow12x-4^3=32\)
\(\Leftrightarrow12x-64=32\)
\(\Leftrightarrow12x=32+64\)
\(\Leftrightarrow12x=96\)
\(\Leftrightarrow x=96:12\)
\(\Leftrightarrow x=8\)
Vậy \(x=8\)
c) \(720:\left[41-\left(2x-5\right)\right]=2^3.5\)
\(\Leftrightarrow720:\left[41-\left(2x-5\right)\right]=8.5\)
\(\Leftrightarrow720:\left[41-\left(2x-5\right)\right]=40\)
\(\Leftrightarrow41-\left(2x-5\right)=720:40\)
\(\Leftrightarrow41-\left(2x-5\right)=18\)
\(\Leftrightarrow2x-5=41-18\)
\(\Leftrightarrow2x-5=23\)
\(\Leftrightarrow2x=23+5\)
\(\Leftrightarrow2x=28\)
\(\Leftrightarrow x=28:2\)
\(\Leftrightarrow x=14\)
Vậy \(x=14\)
BM
0
29 tháng 7 2019
Tìm x thuoc z:
1) \(26-\left|x+9\right|=-13\)
\(\Leftrightarrow\left|x+9\right|=26-\left(-13\right)\)
\(\Leftrightarrow\left|x+9\right|=39\)
\(\Leftrightarrow\left[{}\begin{matrix}x+9=39\\x+9=-39\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=39-9=30\\x=-39-9=-48\end{matrix}\right.\)
Vậy: \(x\in\left\{30;-48\right\}\)
2) \(\left|x+7\right|-13=25\)
\(\Leftrightarrow\left|x+7\right|=25+13=38\)
\(\Leftrightarrow x+7\in\left\{38;-38\right\}\)
\(\Leftrightarrow x\in\left\{31;-45\right\}\)
Vậy:.................
tim x biet
\(1)123-3.\left(x+4\right)=23\)
\(\Leftrightarrow3\left(x+4\right)=123-23\)
\(\Leftrightarrow3\left(x+4\right)=100\)
\(\Leftrightarrow x+4=\frac{100}{3}\)
\(\Leftrightarrow x=\frac{100}{3}-4=\frac{100-12}{3}=\frac{88}{3}\)
Vậy:................
2) Tương tự
KJ
2
S
29 tháng 11 2021
9. (x + 28) = 0
x + 28 = 0: 9
x + 28 = 0
x = 0 – 28
x = -28
Vậy x = -28.
720:[41-(2x-5)]=23.5
720:[41-(2x-5)]=8.5
720:[41-(2x-5)]=40
41-(2x-5)=720:40
41-(2x-5)=18
2x-5=41-18
2x-5=23
2x=23+5
2x=28
x=28:2
x=14
Vậy x=14
14 tháng 9 2015
a) 12 ( 2x - 6 ) - 43= 53
12 ( 2x - 6 ) - 43= 125
12 ( 2x - 6 ) =125+43
12 ( 2x - 6 ) =168
2x - 6=168:12
2x - 6=14
2x=14+6
2x=20
x=20:2
x=10
b) 7 ( 25 - 3x ) = 34 - 25
7 ( 25 - 3x ) = 49
25 - 3x =49:7
25 - 3x =7
3x=25-7
3x=18
x=18:3
x=6
c) ( 3x - 5 ) + 34 + 60 = 53
( 3x - 5 ) + 81 + 1 = 125
( 3x - 5 ) + 81=125-1
( 3x - 5 ) + 81=124
3x - 5=124-81
3x - 5=43
3x=43+5
3x=48
x=48:3
x=16
d) 3x + 2x ( 23 . 5 - 32 . 4 ) + 52 = 44
3x + 2x ( 8 . 5 - 9 . 4 ) + 25 = 256
3x + 2x.4 + 25 = 256
3x + 2x.4=256-25
3x + 2x.4=231
(3+2).x.4=231
5x.4=231
5x=231:4
5x=57,75
x=57,75:5
x=11,55
e) 720 : [ 41 - (2x - 5 ) ] = 23 .5
720 : [ 41 - ( 2x - 5 ) ] =40
41 - ( 2x - 5 )=720:40
41 - ( 2x - 5 )=18
2x - 5=41-18
2x - 5=23
2x=23+5
2x=28
x=28:2
x=14
9 tháng 11 2019
720 : [(5 - 2x) - (-41)] = 23 . 5
720 : [(5 - 2x) + 41] = 8 . 5
720 : [(5 - 2x) + 41] = 40
(5 - 2x) + 41 = 720 : 40
(5 - 2x) + 41 = 18
5 - 2x = 18 - 41
5 - 2x = -23
2x = 5 - (-23) = 5 + 23
2x = 28
x = 28 : 2 = 14
=> x = 14
(2x - 4)3 = 8
(2x - 4)3 = 23
2x - 4 = 2
2x = 2 + 4
2x = 6
x = 6 : 2
x = 3
\(\frac{720}{41-\left(2x-5\right)}=2^3\times5\)
\(\frac{720}{41-2x+5}=8\times5\)
\(46-2x=\frac{720}{40}\)
\(2x=46-18\)
2x = 28
x = 28 : 2
x = 14